U.S. patent application number 16/496842 was filed with the patent office on 2020-01-23 for vibration damping device and bobbin holder system.
This patent application is currently assigned to TMT Machinery, Inc.. The applicant listed for this patent is TMT Machinery, Inc.. Invention is credited to Yukio ISHIDA, Kakeru KAGATA, Shogo KOJIMA.
Application Number | 20200025276 16/496842 |
Document ID | / |
Family ID | 63675533 |
Filed Date | 2020-01-23 |
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United States Patent
Application |
20200025276 |
Kind Code |
A1 |
KOJIMA; Shogo ; et
al. |
January 23, 2020 |
VIBRATION DAMPING DEVICE AND BOBBIN HOLDER SYSTEM
Abstract
A vibration damping device which is able to damp vibration of a
rotating body in a high-speed range and to certainly accelerate the
rotating body to the high-speed range is provided. A vibration
damping device 1 damping vibration of a rotating body 100 includes
an automatic balancer 2 which is configured to cancel out imbalance
of the rotating body 100 when the rotating body rotates 100; a
liquid damper 4 which is coaxially rotatable with the rotating body
100 and includes a collision member 23 provided in a casing 20 in
which liquid 22 is sealed, the liquid colliding with the collision
member 23 when the liquid 22 moves in a circumferential direction;
and a relative rotation unit 5 which is configured to cause the
liquid damper 4 to rotate relative to the rotating body 100.
Inventors: |
KOJIMA; Shogo; (Kyoto-shi,
JP) ; KAGATA; Kakeru; (Kyoto-shi, JP) ;
ISHIDA; Yukio; (Nagakute-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
TMT Machinery, Inc. |
Osaka-shi |
|
JP |
|
|
Assignee: |
TMT Machinery, Inc.
Osaka-shi
JP
|
Family ID: |
63675533 |
Appl. No.: |
16/496842 |
Filed: |
February 22, 2018 |
PCT Filed: |
February 22, 2018 |
PCT NO: |
PCT/JP2018/006425 |
371 Date: |
September 23, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F16F 15/005 20130101;
F16F 15/32 20130101; B65H 54/20 20130101; B65H 2515/50 20130101;
F16F 2222/12 20130101; F16F 15/145 20130101; F16F 2232/02 20130101;
F16F 15/10 20130101; F16F 2222/08 20130101; F16F 2234/02 20130101;
F16F 9/145 20130101; F16F 2228/066 20130101; F16H 1/06 20130101;
F16F 9/12 20130101; F16F 15/31 20130101; F16F 15/16 20130101 |
International
Class: |
F16F 15/10 20060101
F16F015/10; F16F 15/00 20060101 F16F015/00; F16H 1/06 20060101
F16H001/06; F16F 15/31 20060101 F16F015/31; F16F 9/12 20060101
F16F009/12; F16F 9/14 20060101 F16F009/14; F16F 15/14 20060101
F16F015/14; F16F 15/16 20060101 F16F015/16; B65H 54/20 20060101
B65H054/20 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 31, 2017 |
JP |
2017-070446 |
Claims
1. A vibration damping device damping vibration of a rotating body,
comprising: an automatic balancer which is configured to cancel out
imbalance of the rotating body when the rotating body rotates; a
liquid damper which is coaxially rotatable with the rotating body
and includes a collision member provided in a casing in which
liquid is sealed, the liquid colliding with the collision member
when the liquid moves in a circumferential direction; and a
relative rotation unit which is configured to cause the liquid
damper to rotate relative to the rotating body.
2. The vibration damping device according to claim 1, wherein, an
air resistance imparting member which increases air resistance
during rotation of the liquid damper is provided as the relative
rotation unit.
3. The vibration damping device according to claim 2, wherein, the
air resistance imparting member is a plate member having a surface
intersecting with the rotational direction of the liquid
damper.
4. The vibration damping device according to claim 3, wherein, the
plate member is provided on the outer circumferential surface of
the liquid damper.
5. The vibration damping device according to claim 3, wherein, the
plate member is provided on an end face in the axial direction of
the liquid damper.
6. The vibration damping device according to claim 1, wherein, a
brake mechanism is provided as the relative rotation unit, the
brake mechanism including: an electromagnetic effect target which
is provided on the liquid damper and to which an electromagnetic
effect is exerted; and an electromagnetic effector configured to
exert the electromagnetic effect to the electromagnetic effect
target.
7. The vibration damping device according to claim 1, wherein, a
gear mechanism is provided as the relative rotation unit, the gear
mechanism including: a gear portion which is formed on the outer
circumferential surface of the liquid damper; a gear which is
engaged with the gear portion; and a drive unit configured to
generate rotational torque in the liquid damper by rotating the
gear.
8. The vibration damping device according to claim 1, wherein, the
automatic balancer is a ball balancer in which balls are movably
housed in a housing.
9. The vibration damping device according to claim 8, wherein, a
partitioning member is provided to divide the inside of the housing
into plural housing chambers in the circumferential direction, at
least one ball is housed in each of the housing chambers, and the
partitioning member prevents the ball housed in each of the housing
chambers from moving to another housing chamber.
10. The vibration damping device according to claim 1, wherein, the
automatic balancer is a pendulum balancer including pendulums which
are swingable in the circumferential direction of the rotating
body.
11. The vibration damping device according to claim 1, wherein, the
automatic balancer is a ring balancer including ring members which
are rotatable around the rotating body.
12. The vibration damping device according to claim 1, wherein, the
automatic balancer is a liquid balancer in which liquid is movably
sealed in a casing.
13. A bobbin holder system comprising: a bobbin holder to which a
bobbin is attached, the bobbin holder rotating so as to form a
package by winding a yarn made of synthetic fibers onto the bobbin;
and the vibration damping device according to claim 19, which is
attached to the bobbin holder functioning as the rotating body.
14. The bobbin holder system according to claim 13, wherein, the
vibration damping device is attached to a location on the bobbin
holder corresponding to antinode of vibration in a predetermined
resonance mode in which bending of the bobbin holder occurs.
15. The bobbin holder system according to claim 13, wherein, the
bobbin holder is cantilevered, and the vibration damping device is
attached to an end portion on the free end side of the bobbin
holder.
16. The bobbin holder system according to claim 15, wherein, the
liquid damper is attached to a portion on the free end side of the
bobbin holder as compared to the automatic balancer.
17. The bobbin holder system according to claim 13, wherein, the
bobbin holder is supported at both ends, and the vibration damping
device is attached to a substantially central portion in the axial
direction of the bobbin holder.
18. The bobbin holder system according to claim 13, wherein, the
vibration damping device is provided inside the bobbin holder.
19. The vibration damping device according to claim 1, wherein,
vibration of the rotating body rotationally driven by a driver is
suppressed.
Description
TECHNICAL FIELD
[0001] The present invention relates to a vibration damping device
configured to damp vibration of a rotating body and a bobbin holder
system in which the vibration damping device is attached to a
bobbin holder.
BACKGROUND ART
[0002] For example, Patent Literatures 1 and 2 disclose, as a
device for damping vibration of a rotating body, a ball balancer (a
type of an automatic balancer) in which balls are movably housed in
a casing. The ball balancer is capable of damping vibration of the
rotating body as the balls move to positions where imbalance of the
rotating body is canceled out, when the rotating body rotates.
Known examples of the automatic balancer which damps vibration of
the rotating body as the imbalance of the rotating body is canceled
out by a mass body (the balls of the ball balancer) include a
pendulum balancer, a ring balancer, and a liquid balancer, in
addition to the ball balancer.
CITATION LIST
Patent Literatures
[0003] [Patent Literature 1] Japanese Examined Patent Publication
No. H7-114984 [0004] [Patent Literature 2] Japanese Patent No.
4509096
SUMMARY OF INVENTION
Technical Problem
[0005] The automatic balancer described above is effective when,
for example, the rotating body rotates in a high-speed range which
is higher than a natural frequency. However, when the rotating body
rotates in a low-speed range which is on the low speed side of the
high-speed range, the vibration of the rotating body is scarcely
damped, and may be amplified. This is because of a known phenomenon
that the gravity center of the rotating body in the low-speed range
is at a location radially away from the center of the rotating body
(i.e., radially outside) whereas the gravity center of the rotating
body in the high-speed range is on the opposite side over the
center of the rotating body (i.e., radially inside) in the
centrifugal direction. In the high-speed range, as the mass body
such as the balls moves radially outward on account of the
centrifugal force, the center of gravity at a radially outer part
is moved toward the center of the rotating body, with the result
that the vibration of the rotating body is damped. Meanwhile, in
the low-speed range, as the mass body such as the balls moves
radially outward on account of the centrifugal force, the center of
gravity at a radially outer part is moved further away from the
center of the rotating body, with the result that the vibration is
disadvantageously amplified.
[0006] As such, the known automatic balancer succeeds in vibration
damping in the high-speed range but disadvantageously amplify the
vibration in the low-speed range. The vibration during resonance
may be amplified and diverge by the automatic balancer. On this
account, it is impossible to accelerate the rotating body to the
high-speed range beyond the resonance range, and hence it is
impossible to use the rotating body in the high-speed range.
[0007] The present invention has been made in view of this problem,
and an object of the present invention is to provide a vibration
damping device which is able to damp vibration of a rotating body
in a high-speed range and to certainly accelerate the rotating body
to the high-speed range.
Solution to Problem
[0008] A vibration damping device of the present invention is a
vibration damping device damping vibration of a rotating body and
includes: an automatic balancer which is configured to cancel out
imbalance of the rotating body when the rotating body rotates; a
liquid damper which is coaxially rotatable with the rotating body
and includes a collision member provided in a casing in which
liquid is sealed, the liquid colliding with the collision member
when the liquid moves in a circumferential direction; and a
relative rotation unit which is configured to cause the liquid
damper to rotate relative to the rotating body.
[0009] In the present invention, the liquid damper is provided in
addition to the automatic balancer. In the liquid damper, as the
liquid collides with the collision member, part of kinetic energy
is converted to heat energy, with the result that the vibration of
the rotating body is suppressed. The vibration damping effect of
this liquid damper is particularly conspicuous in the resonance
range in which the liquid greatly flows and tends to collide with
the collision member. Furthermore, in the present invention,
because the liquid damper rotates relative to the rotating body
thanks to the relative rotation unit, the orbital revolution of the
rotating body due to whirling of the rotating body does not
coincide with the axial rotation of the liquid damper. It is
therefore possible to prevent the liquid from immovably adhering to
the inner wall surface of the liquid damper due to the centrifugal
force, and to facilitate the collision of the liquid onto the
collision member. As such, the present invention is able to not
only damp the vibration of the rotating body in the high-speed
range by the automatic balancer but also effectively damp the
vibration in the resonance range by the liquid damper. The
acceleration of the rotating body to the high-speed range beyond
the resonance range is therefore ensured.
[0010] The present invention may be arranged such that an air
resistance imparting member which increases air resistance during
rotation of the liquid damper is provided as the relative rotation
unit.
[0011] With this arrangement, the rotational resistance is exerted
against the liquid damper when the liquid damper rotates, and hence
the rotation speed of the liquid damper becomes lower than that of
the rotating body. As a result, the liquid damper rotates relative
to the rotating body.
[0012] The present invention may be arranged such that the air
resistance imparting member is a plate member having a surface
intersecting with the rotational direction of the liquid
damper.
[0013] With this arrangement, rotational resistance is exerted as
air collides with the plate member when the liquid damper rotates.
As a result, the rotation speed of the liquid damper becomes lower
than that of the rotating body, and the liquid damper rotates
relative to the rotating body. Furthermore, because the air
resistance imparting member is the plate member, the air resistance
imparting member is easily constructed.
[0014] The present invention may be arranged such that the plate
member is provided on the outer circumferential surface of the
liquid damper.
[0015] Because the acting position of the air resistance is distant
from the center of the rotating body of the liquid damper, the
torque of the rotational resistance exerted against the liquid
damper is large. The rotation speed of the liquid damper is
therefore efficiently lowered, and the relative rotation of the
liquid damper with respect to the rotating body is further
ensured.
[0016] The present invention may be arranged such that the plate
member is provided on an end face in the axial direction of the
liquid damper.
[0017] This arrangement prevents the vibration damping device from
being upsized in the radial directions, and makes it possible to
downsize the vibration damping device.
[0018] The present invention may be arranged such that a brake
mechanism is provided as the relative rotation unit, the brake
mechanism including: an electromagnetic effect target which is
provided on the liquid damper and to which an electromagnetic
effect is exerted; and an electromagnetic effector configured to
exert the electromagnetic effect to the electromagnetic effect
target.
[0019] When the relative rotation unit is an electromagnetic brake
mechanism as described above, as the brake mechanism exerts the
braking force to the liquid damper when the liquid damper rotates,
the rotation speed of the liquid damper is arranged to be lower
than that of the rotating body. As a result, the liquid damper
rotates relative to the rotating body.
[0020] The present invention may be arranged such that a gear
mechanism is provided as the relative rotation unit, the gear
mechanism including: a gear portion which is formed on the outer
circumferential surface of the liquid damper; a gear which is
engaged with the gear portion; and a drive unit configured to
generate rotational torque in the liquid damper by rotating the
gear.
[0021] As the rotational torque is generated in the liquid damper
by the gear mechanism in this way, the liquid damper rotates
relative to the rotating body.
[0022] The present invention may be arranged such that the
automatic balancer is a ball balancer in which balls are movably
housed in a housing.
[0023] With this arrangement, vibration of the rotating body is
damped as the balls move to positions where imbalance of the
rotating body is canceled out, when the rotating body rotates.
Furthermore, because the ball balancer has a relatively simple
structure among automatic balancers, the structure of the vibration
damping device is simplified.
[0024] The present invention may be arranged such that a
partitioning member is provided to divide the inside of the housing
into plural housing chambers in the circumferential direction, at
least one ball is housed in each of the housing chambers, and the
partitioning member prevents the ball housed in each of the housing
chambers from moving to another housing chamber.
[0025] When the above-described partitioning member is not
provided, the balls may keep turning in the housing when the
rotating body rotates, and may not stay at the positions where the
imbalance of the rotating body is canceled out. With the
above-described partitioning member, the partitioning member
prevents the balls from keep turning, and the balls quickly move to
the positions where the imbalance of the rotating body is canceled
out. When the rotating body is provided crosswise, the balls may
not easily move upward on account of the gravity, depending on the
rotation speed of the rotating body and the mass of the ball, etc.
The influence of the gravity is suppressed by the partitioning
member, because the balls are lifted by the partitioning
member.
[0026] The present invention may be arranged such that the
automatic balancer is a pendulum balancer including pendulums which
are swingable in the circumferential direction of the rotating
body.
[0027] Vibration of the rotating body is damped as the pendulums
swing in the circumferential direction and move to positions where
imbalance of the rotating body is canceled out, when the rotating
body rotates.
[0028] The present invention may be arranged such that the
automatic balancer is a ring balancer including ring members which
are rotatable around the rotating body.
[0029] With this arrangement, vibration of the rotating body is
damped as the ring members rotate around the rotating body and move
to positions where imbalance of the rotating body is canceled out,
when the rotating body rotates.
[0030] The present invention may be arranged such that the
automatic balancer is a liquid balancer in which liquid is movably
sealed in a casing.
[0031] Vibration of the rotating body is damped as the liquid is
spread to cancel out the imbalance of the rotating body when the
rotating body rotates.
[0032] A bobbin holder system of the present invention includes: a
bobbin holder to which a bobbin is attached, the bobbin holder
rotating so as to form a package by winding a yarn made of
synthetic fibers onto the bobbin; and the vibration damping device
described above, which is attached to the bobbin holder functioning
as the rotating body.
[0033] The bobbin holder tends to be used in the high-speed range
which is, for example, equal to or higher than 2000 rpm, and
typically has a natural frequency in the low-speed range which is
on the low speed side of the high-speed range. As the vibration
damping device is attached to the bobbin holder, vibration is
damped in the high-speed range in which the bobbin holder is used,
and acceleration of the bobbin holder to the high-speed range
beyond the resonance range is ensured.
[0034] The present invention may be arranged such that the
vibration damping device is attached to a location on the bobbin
holder corresponding to antinode of vibration in a predetermined
resonance mode in which bending of the bobbin holder occurs.
[0035] Because the liquid damper vibration is damped by the liquid
colliding with the collision members, the vibration damping effect
is enhanced when the liquid damper is attached to a portion where
the vibration is significant. The vibration damping effect of the
liquid damper is therefore improved by attaching the vibration
damping device to a location on the bobbin holder corresponding to
antinode of vibration in the resonance mode (i.e., to a location
where the variation is maximized).
[0036] The present invention may be arranged such that the bobbin
holder is cantilevered, and the vibration damping device is
attached to an end portion on the free end side of the bobbin
holder.
[0037] Because in the liquid damper vibration is damped by the
liquid colliding with the collision members, the vibration damping
effect is enhanced when the liquid damper is attached to a portion
where the vibration is significant. On this account, when the
bobbin holder is cantilevered, the vibration damping device is
attached to an end portion on the free end side of the bobbin
holder, where the vibration is most significant. This makes it
possible to improve the vibration damping effect of the liquid
damper.
[0038] The present invention may be arranged such that the liquid
damper is attached to a portion on the free end side of the bobbin
holder as compared to the automatic balancer.
[0039] With this arrangement, the vibration damping device is
attached to the portion where the vibration is most significant.
This makes it possible to further improve the vibration damping
effect of the liquid damper.
[0040] The present invention may be arranged such that the bobbin
holder is supported at both ends, and the vibration damping device
is attached to a substantially central portion in the axial
direction of the bobbin holder.
[0041] Because in the liquid damper vibration is damped by the
liquid colliding with the collision members, the vibration damping
effect is enhanced when the liquid damper is attached to a portion
where the vibration is significant. On this account, when the
bobbin holder is supported at the both ends, the vibration damping
device is attached to the central portion of the bobbin holder,
where the vibration is most significant. This makes it possible to
improve the vibration damping effect of the liquid damper.
[0042] The present invention may be arranged such that the
vibration damping device is provided inside the bobbin holder.
[0043] The vibration damping effect for the bobbin holder is
improved by providing the vibration damping device inside the
bobbin holder in this way. Furthermore, the following effects are
attained: improvement in the degree of freedom in the attachment
position of the bobbin on the bobbin holder; increase in the
maximum number of the bobbins attachable to the bobbin holder; and
improvement in workability when the bobbin is attached to and
detached from the bobbin holder.
BRIEF DESCRIPTION OF DRAWINGS
[0044] FIG. 1 is a cross section of a vibration damping device of
an embodiment.
[0045] FIG. 2 is a cross section taken along a line II-II in FIG.
1.
[0046] FIG. 3 is a cross section taken along a line III-III in FIG.
1.
[0047] FIG. 4 is a side view showing a testing machine used in a
verification experiment.
[0048] FIG. 5 is a graph showing experimentation results regarding
a vibration damping effect.
[0049] FIG. 6 is a side view showing a bobbin holder system to
which the vibration damping device is attached.
[0050] FIG. 7 is a top view showing a modification of the relative
rotation unit.
[0051] FIG. 8 is a perspective view showing a modification of the
relative rotation unit.
[0052] FIG. 9 is a top view showing a modification of the relative
rotation unit.
[0053] FIG. 10 is a top view showing a modification of the relative
rotation unit.
[0054] FIG. 11 is a top view showing a modification of an automatic
balancer.
[0055] FIG. 12 is a side view showing a modification of the bobbin
holder system.
[0056] FIG. 13 is a side view showing a modification of the bobbin
holder system.
DESCRIPTION OF EMBODIMENTS
Embodiment
[0057] The following will describe an embodiment of a vibration
damping device related to the present invention. FIG. 1 is a cross
section of the vibration damping device of the present embodiment,
and is taken along the axial direction of a rotating body 100. FIG.
2 is a cross section taken along a line II-II in FIG. 1, and FIG. 3
is a cross section taken along a line III-III in FIG. 1. While the
explanations below presuppose that the axial direction of the
rotating body 100 is identical with the up-down direction, the
axial direction of the rotating body 100 may be a direction
different from the up-down direction.
[0058] The vibration damping device 1 of the present embodiment is
attached to the outer circumferential surface of the rotating body
100 and includes a ball balancer 2 and a liquid damper system 3.
The ball balancer 2 is an automatic balancer in which balls 11 are
movably housed in a cylindrical housing 10 which is fixed to the
rotating body 100. As shown in FIG. 2, in the housing 10, plural
(two in the present embodiment) partitioning members 12 are
provided at regular intervals in the circumferential direction.
With this, the internal space of the housing 10 is divided into
plural (two in the present embodiment) housing chambers 13 in the
circumferential direction. One ball 11 is housed in each housing
chamber 13. The ball 11 housed in each housing chamber 13 cannot
move to another housing chamber 13 on account of the partitioning
member 12.
[0059] When the ball balancer 2 structured as described above is
attached to the rotating body 100, the balls 11 move to positions
where imbalance of the rotating body 100 is canceled out when the
rotating body 100 rotates, with the result that vibration on
account of the imbalance of the rotating body 100 is suppressed.
However, as described above, the automatic balancer such as the
ball balancer 2 exerts a vibration damping effect when the rotating
body 100 rotates in a high-speed range, but the vibration of the
rotating body 100 is rarely damped and rather amplified when the
rotating body 100 rotates in a low-speed range. For this reason,
when the natural frequency of the rotating body 100 is in the
low-speed range, the vibration during resonance may be amplified by
the automatic balancer and diverge, and the rotating body 100
cannot be accelerated to the high-speed range beyond the resonance
range.
[0060] To solve this problem, the vibration damping device 1 of the
present embodiment includes the liquid damper system 3 in addition
to the ball balancer 2. The liquid damper system 3 includes a
liquid damper 4 and plate members 5 which form a relative rotation
unit (air resistance imparting member). The liquid damper 4 is
arranged such that liquid 22 is sealed in an internal space 21 of a
casing 20. The liquid damper 4 is attached to the rotating body 100
to be coaxially rotatable with the rotating body 100. While the
liquid 22 in the present embodiment is water, the liquid 22 may not
be water.
[0061] The casing 20 includes a casing main body 20a and a lid
member 20b, and is on the whole cylindrical. The casing main body
20a is open top, and the lid member 20b is fixed to the upper
surface of the casing main body 20a by a bolt, etc. to close the
opening. The casing 20 has the annular internal space 21, and the
rotating body 100 penetrates a central portion of the casing
20.
[0062] A cylindrical boss 31 is fixed to the outer circumferential
surface of the rotating body 100. To the outer circumferential
surface of the boss 31, two bearings, i.e., upper and lower
bearings 32 are fixed. While the bearings 32 in the present
embodiment are ball bearings each having balls 32a, the bearings 32
may not be ball bearings. At an upper part of the outer
circumferential surface of the boss 31, a stepped portion 31a is
formed. The upper bearing 32 is externally fitted to the boss 31
while being in contact with the stepped portion 31a. Below the
upper bearing 32, a first spacer 33, the lower bearing 32, a second
spacer 34, and an engaging member 35 are externally fitted to the
boss 31 in this order. The engaging member 35 is a C-ring, for
example, and is fitted to an annular groove 31b formed in the outer
circumferential surface of the boss 31.
[0063] A biasing member 36 is provided between the second spacer 34
and the engaging member 35. The biasing member 36 is formed of, for
example, a disc spring or a corrugated washer. As the two bearings
32 are biased toward the stepped portion 31a by the biasing member
36, the bearings 32 are suitably pre-loaded. An O-ring 37 is
provided radially inside each bearing 32. The inner race 32b of
each bearing 32 is fixed to the boss 31, whereas the outer race 32c
is fixed to the casing 20.
[0064] As shown in FIG. 3, plural (eight in the present embodiment)
plate-shaped collision members 23 are fixed to an inner wall
surface 20c which is the outer one of the inner wall surfaces of
the casing 20 in the radial direction, so as to protrude from the
inner wall surface 20c toward the internal space 21. The liquid 22
may collide with the collision members 23 when moving in the
circumferential direction. The collision members 23 are provided at
regular intervals in the circumferential direction. The number and
locations of the collision members 23 are not limited to the
above-mentioned number and locations, and may be suitably
changed.
[0065] Plural (eight in the present embodiment) plate members 5
each having a surface intersecting with the rotational direction of
the liquid damper 4 are fixed to the outer circumferential surface
of the liquid damper 4 (casing 20) to protrude radially outward
along the radial directions. The plate members 5 are provided at
regular intervals in the circumferential direction. The number and
locations of the plate members 5 are not limited to the
above-mentioned number and locations, and may be suitably
changed.
[0066] In the liquid damper system 3 with the structure described
above, as the rotating body 100 is rotationally driven by an
unillustrated driver, the liquid damper 4 is rotated together by
the friction of the bearings 32. As a result of the rotation of the
liquid damper 4, air resistance is exerted against the plate
members 5 which form the relative rotation unit (air resistance
imparting member), and rotational resistance is exerted against the
liquid damper 4. The rotational resistance increases as the
rotation speed of the liquid damper 4 increases. When the magnitude
of the rotational resistance exceeds the friction force of the
bearings 32, the rotation speed of the liquid damper 4 starts to
lag behind the rotating body 100. As a result, the liquid damper 4
starts to rotate relative to the rotating body 100.
[0067] In the liquid damper 4, as the liquid 22 collides with the
collision members 23 while the rotating body 100 rotates, part of
kinetic energy is converted to heat energy, with the result that
the vibration of the rotating body 100 is suppressed. In
particular, because the liquid damper 4 rotates relative to the
rotating body 100 (non-synchronous rotation) as described above,
the orbital revolution of the rotating body 100 due to whirling of
the rotating body 100 does not coincide with the axial rotation of
the liquid damper 4. It is therefore possible to prevent the liquid
22 from immovably adhering to the inner wall surface 20c of the
casing 20 due to the centrifugal force, and to facilitate the
collision of the liquid 22 onto the collision members 23.
[0068] As shown in FIG. 4, an experiment was done to verify the
vibration damping effect of the rotating body 100. A testing
machine used in the verification experiment is arranged such that
the rotating body 100 extending along the horizontal direction is
rotatably supported by both two supporters 101 on the left and
right sides, and the vibration damping device 1 is attached to a
substantially central portion in the axial direction of the
rotating body 100. FIG. 5 is a graph showing experimentation
results regarding a vibration damping effect. The verification
experiment was done in a condition that neither the ball balancer 2
nor the liquid damper system 3 was attached to the rotating body
100 ("Nothing" in FIG. 5), in a condition that only the ball
balancer 2 was attached to the rotating body 100 ("Only Ball
Balancer" in FIG. 5), and in a condition that both of the ball
balancer 2 and the liquid damper system 3 are attached to the
rotating body 100 ("Ball Balancer+Liquid Damper System" in FIG. 5).
In the verification experiment, a vibration level of the rotating
body 100 was measured when steady rotation was achieved with each
rotation number. The natural frequency of the rotating body 100
used in the experiment was 1380 rpm.
[0069] As shown in FIG. 5, when neither the ball balancer 2 nor the
liquid damper system 3 was attached to the rotating body 100,
vibration diverged in a resonance range including the natural
frequency. Meanwhile, when only the ball balancer 2 was attached to
the rotating body 100, the vibration level was decreased in a
high-speed range which was on the high speed side of the natural
frequency and was equal to or higher than about 2000 rpm, as
compared to the case where nothing was attached. However, in a
low-speed range which was on the low speed side of the high-speed
range and was equal to or lower than about 2000 rpm, the vibration
level was rather increased with the ball balancer 2, and the
vibration diverged in a wide resonance range as compared to the
case where nothing was attached. In other words, it was verified
that, when only the ball balancer 2 was attached, even though the
vibration damping effect was attained when the rotating body 100
rotated in the high-speed range, the vibration of the rotating body
100 was rather amplified when the rotating body 100 rotated in the
low-speed range.
[0070] As such, when nothing was attached to the rotating body 100
or when only the ball balancer 2 was attached thereto, the
vibration of the rotating body 100 diverged in the resonance range.
It was therefore impossible to accelerate the rotating body 100 to
reach 2000 rpm or higher beyond the resonance range. In the
experiment, even though vibration occurred in the resonance range,
the vibration level in the high-speed range was measured in a state
that the rotating body 100 was accelerated to a rotation number
higher than the resonance range while the vibration of the rotating
body 100 was forcibly suppressed.
[0071] When both of the ball balancer 2 and the liquid damper
system 3 were attached to the rotating body 100, the vibration
level was decreased in the low-speed range as compared to the case
where only the ball balancer 2 was attached. In particular, in the
resonance range, the vibration level was suppressed to a level at
which divergence of the vibration was prevented even in steady
rotation, and hence acceleration of the rotating body 100 to the
high-speed range beyond the resonance range was possible. In the
high-speed range, while the vibration damping effect thanks to the
attachment of the liquid damper system 3 was not observed, the
vibration damping effect was attained by the ball balancer 2 which
was effective in the high-speed range. As such, it was verified
that the vibration was effectively damped in a wide range from the
low-speed range to the high-speed range, with the concurrent use of
the ball balancer 2 effective in the high-speed range and the
liquid damper system 3 effective in the resonance range.
[0072] In the experiment, the weight of the rotating body 100 was
about 2 kilograms and the weight of the water as the liquid 22
sealed in the liquid damper 4 was about 150 grams. A significant
vibration damping effect was therefore achieved with the liquid 22
having weight less than 10% of the weight of the rotating body 100.
A significant vibration damping effect was achieved with a small
amount of the liquid 22, presumably because the apparent weight of
the liquid 22 was increased by the centrifugal force and the energy
of collision was increased.
[0073] Lastly, the following will describe a case where the
above-described vibration damping device 1 is applied to a bobbin
holder which is the rotating body 100. FIG. 6 is a side view
showing a bobbin holder system 60 to which the vibration damping
device 1 is attached. In the bobbin holder system 60, the vibration
damping device 1 is attached to a bobbin holder 61. The bobbin
holder 61 extends along the horizontal direction and is rotatably
supported by both of two supporters 62 on the left and right sides.
The vibration damping device 1 is attached to a substantially
central portion in the axial direction of the bobbin holder 61. On
the respective sides of the vibration damping device 1, bobbins 63
are attached to be aligned in the axial direction. As the bobbin
holder 61 is rotated, yarns Y constituted by synthetic fibers made
of polyester, etc. are wound onto the bobbins 63, with the result
that plural packages are formed.
Advantageous Effects
[0074] In the vibration damping device 1 of the present embodiment,
the liquid damper 4 is provided in addition to the ball balancer 2
(automatic balancer). In the liquid damper 4, as the liquid 22
collides with the collision members 23, part of kinetic energy is
converted to heat energy, with the result that the vibration of the
rotating body 100 is suppressed. The vibration damping effect of
this liquid damper 4 is particularly conspicuous in the resonance
range in which the liquid 22 greatly flows and tends to collide
with the collision members 23. Furthermore, in the vibration
damping device 1, because the liquid damper 4 rotates relative to
the rotating body 100 thanks to the plate members 5 (relative
rotation unit), the orbital revolution of the rotating body 100 due
to whirling of the rotating body 100 does not coincide with the
axial rotation of the liquid damper 4. It is therefore possible to
prevent the liquid 22 from immovably adhering to the inner wall
surface 20c of the liquid damper 4 due to the centrifugal force,
and to facilitate the collision of the liquid 22 onto the collision
members 23. On this account, the vibration is effectively
suppressed even during constant rotation of the rotating body 100
in the resonance range. As such, the vibration damping device 1 is
able to not only damp the vibration of the rotating body 100 in the
high-speed range by the ball balancer 2 but also effectively damp
the vibration in the resonance range by the liquid damper 4. The
acceleration of the rotating body 100 to the high-speed range
beyond the resonance range is therefore ensured.
[0075] In the present embodiment, the plate members 5 (air
resistance imparting member) as the relative rotation unit of the
present invention are provided to increase the air resistance when
the liquid damper 4 rotates. With this arrangement, the rotational
resistance is exerted against the liquid damper 4 when the liquid
damper 4 rotates, and hence the rotation speed of the liquid damper
4 becomes lower than that of the rotating body 100. As a result,
the liquid damper 4 rotates relative to the rotating body 100.
[0076] In the present embodiment, the plate members 5 each having a
surface intersecting with the rotational direction of the liquid
damper 4 are provided as the air resistance imparting member of the
present invention. With this arrangement, rotational resistance is
exerted as air collides with the plate members 5 when the liquid
damper 4 rotates. As a result, the rotation speed of the liquid
damper 4 becomes lower than that of the rotating body 100, and the
liquid damper 4 rotates relative to the rotating body 100.
Furthermore, because the air resistance imparting member is formed
by the plate members 5, the air resistance imparting member is
easily constructed.
[0077] In the present embodiment, the plate members 5 are provided
on the outer circumferential surface of the liquid damper 4.
Because the acting positions of the air resistance are distant from
the center of the rotating body 100 of the liquid damper 4, the
torque of the rotational resistance exerted against the liquid
damper 4 is large. The rotation speed of the liquid damper 4 is
therefore efficiently lowered, and the relative rotation of the
liquid damper 4 with respect to the rotating body 100 is further
ensured.
[0078] In the present embodiment, the ball balancer 2 in which the
balls 11 are movably housed in the housing 10 is the automatic
balancer. It is therefore possible to damp vibration of the
rotating body 100 as the balls 11 move to positions where imbalance
of the rotating body 100 is canceled out, when the rotating body
100 rotates. Furthermore, because the ball balancer 2 has a
relatively simple structure among automatic balancers, the
structure of the vibration damping device 1 is simplified.
[0079] In the present embodiment, the partitioning members 12 are
provided to partition the internal space of the housing 10 into
plural housing chambers 13 in the circumferential direction, at
least one ball 11 is housed in each of the housing chambers 13, and
the partitioning members 12 are arranged to prevent the ball 11
housed in the each housing chamber 13 from moving to another
housing chamber 13. With this arrangement, the partitioning members
12 prevent the balls 11 from keep turning, and the balls 11 quickly
move to the positions where the imbalance of the rotating body 100
is canceled out. When the rotating body 100 is provided crosswise
as shown in FIG. 4, the balls 11 may not easily move upward on
account of the gravity, etc., depending on the rotation speed of
the rotating body 100 and the mass of the ball 11. The influence of
the gravity is suppressed by the partitioning members 12, because
the balls 11 are lifted by the partitioning members 12.
[0080] In the present embodiment, the vibration damping device 1 is
attached to the rotating body 100 or the bobbin holder 61 which
functions as the rotating body 100. The bobbin holder 61 tends to
be used in the high-speed range which is, for example, equal to or
higher than 2000 rpm, and typically has a natural frequency in the
low-speed range which is on the low speed side of the high-speed
range. As the vibration damping device 1 is attached to the bobbin
holder 61, vibration is damped in the high-speed range in which the
bobbin holder 61 is used, and acceleration of the bobbin holder 61
to the high-speed range beyond the resonance range is ensured.
[0081] In the present embodiment, the bobbin holder 61 is supported
at the both ends and the vibration damping device 1 is attached to
a substantially central portion in the axial direction of the
bobbin holder 61. Because in the liquid damper 4 vibration is
damped by the liquid 22 colliding with the collision members 23,
the vibration damping effect is enhanced when the liquid damper 4
is attached to a portion where the vibration is significant. On
this account, when the bobbin holder 61 is supported at the both
ends, the vibration damping device 1 is attached to the central
portion of the bobbin holder 61, where the vibration is most
significant. This makes it possible to improve the vibration
damping effect of the liquid damper 4.
OTHER EMBODIMENTS
[0082] The following will describe modifications of the
above-described embodiment.
[0083] (1) In the embodiment above, the plate members 5 are
provided along radial directions. Alternatively, as shown in FIG.
7(a), in place of the radially-extending plate members 5, plate
members 6 may be provided. Each of the plate members 6 is inclined
toward the downstream side in the rotational direction of the
liquid damper 4 from the base end which is closest to the center of
the rotating body 100 of the liquid damper 4. With these plate
members 6, escape of air radially outward along the plate members 6
is suppressed when the liquid damper 4 rotates. Furthermore, as
indicated by an outlined arrow in FIG. 7, air tends to be trapped
between each plate member 6 and the liquid damper 4, with the
result that more air resistance is exerted against the plate
members 6.
[0084] (2) In addition to the plate members 5 of the embodiment
above, fluid blowing units 7 may be provided as shown in FIG. 7(b).
The fluid blowing units 7 are provided around the liquid damper 4,
and blow fluid such as air from outlets 7a. As each of the outlets
7a is provided to blow fluid in a direction substantially opposite
to the rotational direction of the liquid damper 4, the fluid
blowing units 7 are able to exert hydraulic pressure against the
plate members 5 in the direction opposite to the rotational
direction of the liquid damper 4. This increases the rotational
resistance exerted against the plate members 5, and hence the
relative rotation of the liquid damper 4 with respect to the
rotating body 100 is further ensured. The number and locations of
the fluid blowing units 7 may be different from those shown in FIG.
7(b). For example, only one fluid blowing unit 7 may be
provided.
[0085] (3) While in the embodiment above the plate members 5 are
provided on the outer circumferential surface of the liquid damper
4, plate members 8 may be provided on an end face (top or bottom
surface) in the axial direction of the liquid damper 4 as shown in
FIG. 8. While in FIG. 8 the plate members 8 are provided on the top
surface 4a of the liquid damper 4, the plate members 8 may be
provided on the bottom surface in addition to or in place of those
on the top surface 4a. This arrangement prevents the vibration
damping device 1 from being upsized in the radial directions, and
makes it possible to downsize the vibration damping device 1.
[0086] (4) While in the embodiment above the plate members 5 (air
resistance imparting member) are provided as the relative rotation
unit by which the liquid damper 4 is rotated relative to the
rotating body 100, the relative rotation unit may have a different
structure. For example, an electromagnetic brake mechanism 40 may
be provided as the relative rotation unit as shown in FIG. 9. This
brake mechanism 40 includes a conductor (electromagnetic effect
target) provided on the outer circumferential surface of the liquid
damper 4, a coil 42 (electromagnetic effector) provided to be
distanced from the outer circumferential surface of the liquid
damper 4, and a current controller 43 configured to control a
current supplied to the coil 42. The numbers and locations of the
conductor 41 and the coil 42 may be different from those shown in
FIG. 9, and are suitably changeable. For example, plural coils 42
may be provided at regular intervals along the circumferential
direction of the liquid damper 4.
[0087] When a current is supplied to the coil 42 by the current
controller 43, magnetic force acting between a magnetic flux
generated around the coil 42 on account of electromagnetic
induction and a magnetic flux due to an eddy current generated at
the conductor 41 on the liquid damper 4 functions as braking force.
As the brake mechanism 40 exerts the braking force to the liquid
damper 4 when the liquid damper 4 rotates, the rotation speed of
the liquid damper 4 is arranged to be lower than that of the
rotating body 100. As a result, the liquid damper 4 rotates
relative to the rotating body 100. In this regard, large braking
force can be obtained when the conductor 41 is formed of a magnetic
body, because a large eddy current is generated.
[0088] In connection with the above, the magnitude of a magnetic
field generated at the coil 42 can be changed by changing the
current supplied to the coil 42 by the current controller 43, and
this makes it possible to change the braking force acting between
the conductor 41 and the coil 42. It is therefore possible to
adjust the rotation speed of the liquid damper 4 in accordance with
the state of vibration of the rotating body 100, and to further
improve the vibration damping effect.
[0089] The electromagnetic effect target provided on the outer
circumferential surface of the liquid damper 4 may be not the
conductor 41 but a permanent magnet. With this arrangement, large
brake torque can be obtained by suitably controlling the frequency
of an alternating current supplied to the coil 42 by the current
controller 43 connected to the coil 42. Furthermore, the
electromagnetic effector may be not the coil 42 but a permanent
magnet. With this arrangement, the current controller 43 can be
omitted and the relative rotation unit can be constructed
relatively easily.
[0090] Alternatively, a coil may be provided in place of the
conductor 41 as the electromagnetic effect target on the liquid
damper 4, and a permanent magnet may be provided in place of the
coil 42 as the electromagnetic effector exerting an electromagnetic
effect to the electromagnetic effect target. In this case, the
rotation speed of the liquid damper 4 is adjustable by moving the
permanent magnet and changing the distance between the permanent
magnet and the coil on the liquid damper 4.
[0091] (5) A gear mechanism 50 may be provided as the relative
rotation unit which causes the liquid damper 4 to rotate relative
to the rotating body 100, as shown in FIG. 10. This gear mechanism
includes gear portions 4b formed on the outer circumferential
surface of the liquid damper 4, a gear 51 engaged with the gear
portions 4b, a rotation shaft 52 which is connected to the gear 51
and is substantially parallel to the rotating body 100, and a motor
53 (drive unit) which has an unillustrated output shaft connected
to the rotation shaft 52 and rotationally drives the rotation shaft
52. A housing (not illustrated) of the motor 53 is, for example,
attached to the rotating body 100 via a bearing with substantially
zero friction. The housing is provided so that the motor 53 does
not change its position when the liquid damper 4 rotates.
[0092] The gear 51 rotates in the direction shown in FIG. 10 as the
liquid damper 4 rotates. In this regard, when the motor 53 is
driven at a frequency lower than the rotation frequency of the gear
51 which is in sync with the rotation of the liquid damper 4, the
motor 53 functions as a brake. Rotational resistance torque is
therefore exerted to the liquid damper 4 which is rotated by the
rotating body 100, with the result that the rotation speed of the
liquid damper 4 becomes lower than that of the rotating body 100.
As a result, the liquid damper 4 rotates relative to the rotating
body 100.
[0093] The motor 53 is preferably a variable-speed motor in which
the rotation speed of the output shaft is variable. With this
arrangement, the rotation speed of the gear 51 is changeable, and
the rotation speed of the liquid damper 4 is changeable. It is
therefore possible to adjust the rotation speed of the liquid
damper 4 in accordance with the state of vibration of the rotating
body 100, and to further improve the vibration damping effect.
[0094] (6) In the embodiment above, the collision members 23
protrude toward the internal space 21 from the inner wall surface
20c which is outer one of the inner wall surfaces of the casing in
the radial direction. Alternatively, the collision members 23 may
protrude toward the internal space 21 from the inner one of the
inner wall surfaces of the casing 20 in the radial direction, or
may protrude toward the internal space 21 from the ceiling surface
or bottom surface of the casing 20. Alternatively, the collision
member may be a plate-shaped member which is provided across the
entirety of the space between the inner wall surface which is the
outer one in the radial direction and the inner wall surface which
is the inner one in the radial direction, and has an opening or a
notch portion circumferentially penetrating the plate-shaped
member. The collision member may be not plate-shaped but columnar
or block-shaped. Furthermore, the collision member may be an uneven
portion or a corrugated portion formed on the side surface or the
bottom surface of the casing 20.
[0095] (7) In the embodiment above, the internal space 21 of the
casing 20 is a single chamber. Alternatively, a partition wall may
be provided along the circumferential direction of the internal
space 21 to radially divide the internal space 21 into plural
spaces. In this case, the collision member 23 is provided in each
of the spaces formed by the division.
[0096] (8) While in the embodiment above the rotation speed of the
liquid damper 4 is arranged to be lower than the rotation speed of
the rotating body 100, the liquid damper 4 may be arranged to
rotate relative to the rotating body 100 by setting the rotation
speed of the liquid damper 4 to be higher than that of the rotating
body 100. For example, the direction of blowing air out from each
fluid blowing unit 7 shown in FIG. 7(b) may be changed to exert the
hydraulic pressure in the rotational direction of the liquid damper
4. Alternatively, when the gear mechanism 50 (see FIG. 10) is used
as the relative rotation unit, the rotation speed of the liquid
damper 4 may be arranged to be higher than that of the rotating
body 100 by using the motor 53.
[0097] The rotational direction of the liquid damper 4 may be
opposite to the rotational direction of the rotating body 100. For
example, the liquid damper 4 may be rotated in the direction
opposite to the rotational direction of the rotating body 100 by
increasing the speed of fluid blown out from the fluid blowing
units 7 shown in FIG. 7(b). Alternatively, when the gear mechanism
50 (see FIG. 10) is used as the relative rotation unit, the
rotational direction of the liquid damper 4 may be arranged to be
opposite to that of the rotating body 100 by using the motor
53.
[0098] (9) In the embodiment above, as shown in FIG. 2, the inside
of the housing 10 of the ball balancer 2 is divided into two
housing chambers 13 in the circumferential direction, and one ball
11 is housed in each housing chamber 13. In this regard, the number
of the housing chambers 13 may be three or more, and the number of
the balls 11 housed in each housing chamber 13 may not be one, and
may be two or more. The inside of the housing 10 may not be divided
into plural housing chambers 13. The inside of the housing 10 may
be a single space, without the partitioning members 12. In this
case, two or more balls 11 are housed in the housing 10.
[0099] (10) In the embodiment above, the ball balancer 2 is
provided as the automatic balancer. In this regard, the automatic
balancer of the vibration damping device 1 may have a different
structure on condition that the imbalance of the rotating body 100
is canceled out as a mass body moves around the rotating body 100
when the rotating body 100 rotates. For example, in place of the
ball balancer 2, a pendulum balancer 80 shown in FIG. 11(a), a ring
balancer 90 shown in FIG. 11(b), or an unillustrated liquid
balancer may be used.
[0100] As shown in FIG. 11(a), the pendulum balancer 80 includes
plural pendulums 81 each of which is capable of swinging in the
circumferential direction. The pendulums 81 are attached to a boss
portion 82a of a cylindrical casing 82 fixed to the rotating body
100, and each swings in the circumferential direction about a
fulcrum 83. Vibration of the rotating body 100 is damped as the
pendulums 81 swing in the circumferential direction and move to
positions where imbalance of the rotating body 100 is canceled out,
when the rotating body 100 rotates.
[0101] As shown in FIG. 11(b), the ring balancer 90 includes ring
members 91 which are rotatable around the rotating body 100. The
ring members 91 are aligned in the axial direction of the rotating
body 100 and the rotating body 100 are provided inside the ring
members 91. To the rotating body 100, an unillustrated engaging
member is attached to restrict the movement of the ring members 91
in the axial direction. Vibration of the rotating body 100 is
damped as the ring members 91 rotate around the rotating body 100
and move to positions where imbalance of the rotating body 100 is
canceled out, when the rotating body 100 rotates.
[0102] The liquid balancer is arranged so that liquid is movably
sealed in a casing. Vibration of the rotating body 100 is damped as
the liquid is spread to cancel out the imbalance of the rotating
body 100 when the rotating body 100 rotates. A balancer in which
particles are sealed in place of liquid is also able to damp the
vibration of the rotating body 100 on the same principle as the
liquid balancer.
[0103] (11) While in the embodiment above the vibration damping
device 1 is attached to the substantially central portion in the
axial direction of the bobbin holder 61 supported at the both ends
as shown in FIG. 6, the attaching position of the vibration damping
device 1 may be suitably changed.
[0104] The bobbin holder 61 may not be supported at the both ends.
For example, the bobbin holder 61 may be cantilevered by a
supporter 62 as shown in FIG. 12. In this case, the vibration
damping device 1 is preferably attached to an end portion on the
free end side of the bobbin holder 61 where vibration tends to be
significant, because the vibration damping effect of the liquid
damper 4 is enhanced. The vibration damping effect of the liquid
damper 4 is further enhanced by attaching the liquid damper 4
(liquid damper system 3) at a location on the free end side of the
bobbin holder 61 as compared to the ball balancer 2. Alternatively,
the vibration damping device 1 may be attached to an end portion on
the fixed end side of the bobbin holder 61 or at a central portion
of the bobbin holder 61, and the liquid damper 4 (liquid damper
system 3) may be attached to a location on the fixed end side of
the bobbin holder 61 as compared to the ball balancer 2.
[0105] When there is a predetermined resonance mode in which
bending of the bobbin holder 61 occurs, the vibration damping
effect of the liquid damper 4 is improved by attaching the
vibration damping device 1 to a location on the bobbin holder 61
corresponding to antinode of vibration in the resonance mode, i.e.,
to a location where the variation is maximized. The central portion
of the bobbin holder 61 when it is supported at the both ends and
the end portion on the free end side of the bobbin holder 61 when
it is cantilevered are considered to be more or less equivalent to
the location of the antinode.
[0106] As shown in FIG. 13, the bobbin holder 61 may include a
shaft portion 61a and a cylindrical portion 61b, and the vibration
damping device 1 may be provided inside the bobbin holder 61 when
there is a space between the shaft portion 61a and the cylindrical
portion 61b, where the vibration damping device 1 can be provided.
As such, the vibration damping effect for the bobbin holder 61 is
improved by providing the vibration damping device 1 inside the
bobbin holder 61. Furthermore, when the vibration damping device 1
is provided inside the bobbin holder 61, the following effects are
attained: improvement in the degree of freedom in the attachment
positions of the bobbins 63 on the bobbin holder 61; increase in
the maximum number of the bobbins 63 attachable to the bobbin
holder 61; and improvement in workability when the bobbins 63 are
attached to and detached from the bobbin holder 61.
[0107] (12) While the embodiment describes the cases where the
vibration damping device 1 is attached to the bobbin holder 61, the
vibration damping device 1 may be attached to a rotating body 100
which is not the bobbin holder 61.
REFERENCE SIGNS LIST
[0108] 1 vibration damping device [0109] 2 ball balancer (automatic
balancer) [0110] 3 liquid damper system [0111] 4 liquid damper
[0112] 4b gear portion [0113] 5, 6, 8 plate member (relative
rotation unit, air resistance imparting member) [0114] 10 housing
[0115] 11 ball [0116] 12 partitioning member [0117] 13 housing
chamber [0118] 20 casing [0119] 22 liquid [0120] 23 collision
member [0121] 40 brake mechanism (relative rotation unit) [0122] 41
conductor (electromagnetic effect target) [0123] 42 coil
(electromagnetic effector) [0124] 50 gear mechanism (relative
rotation unit) [0125] 51 gear [0126] 53 motor (drive unit) [0127]
60 bobbin holder system [0128] 61 bobbin holder [0129] 63 bobbin
[0130] 100 rotational body [0131] Y yarn
* * * * *